miguelszerman
Why do functions inside a keywords list passed as arguments to `if` aren't called immediately?
Why do functions inside the keywords list passed as arguments to if aren’t called immediately? Is this unique to if?
# example.exs
defmodule Call do
def this(), do: IO.puts("this")
def that(), do: IO.puts("that")
end
defmodule Example do
def fun(keywords), do: :ok
end
IO.puts(
Example.fun(
[do: Call.this(), else: Call.that()]
)
)
IO.puts(
if(
true,
[do: Call.this(), else: Call.that()]
)
)
Output from file:
$ elixir example.exs
this
that
ok
this # expected 'this' and 'that' always to be called independently of the if the boolean evaluation
ok
Marked As Solved
al2o3cr
if is not a function, it is a macro. Macros run at compile-time and receive the AST representation of their arguments without any evaluation.
The guide has a good example of implementing an if-like macro:
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